Fireproof-floor construction.



Patented Sept. I9, |899.

A. L. JOHNSON.

FIBEPBOOF FLOOR CONSTRUCTION.

(Application led Nov. 10, 1898.)

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UNITED STATES PATENT OFFICEC ALBERT L. JOHNSON, OF ST. LOUIS, MISSOURI,ASSIGNOR OF ONEHALF TO D. E. GARRISON, SR., OF SAME PLACE.

FlREPROOF-FLOOR CONSTRUCTION.

SPECIFICATION forming part of Letters Patent No. 633,285, datedSeptember 19, 1899.

Application tiled November l0, 1898. Serial No. 696,067. (No model.)

To all whom, it may concern:

Be itknown that I, ALBERT L. JOHNSON, a citizen of the United States,and a residentof the city of St. Louis and State of Missouri,

have invented a new and useful Improvement in Fireproof-FloorConstruction, of which the following is a specification.

My invention relates to reproof door and ceiling construction, and hasfor its principal ro objects to economize labor and material, to reduceweight, and to increase the strength and durability of the structure.

My invention consists principally in transversely-corrugated metallicbars ofsubstani5 tially uniform vthickness throughout their lengthembedded in the lower portion of concrete slabs or in ribs on the underside thereof. It also consists in a floor and ceiling constructionwherein ribs of concrete extend from 2o I-beam to I-beam and haveembedded therein metallic rods from which ceiling-hangers are suspended,as hereinafter claimed.

It also consists in the parts and in the combinations of parts describedand claimed 2 5 herein.

In the accompanying drawings, which form part of this specification andwherein like symbols refer to like parts wherever they occur, Figure 1is a perspective view of my floor 3o system.

Fig. 3 is a longitudinal section thereof. Fig. et is la cross-sectionsimilar to Fig. 2 except that the main oor layer has a sheet ofexpanded-metal embedded therein. Figs. 5 and 3 5 6 are enlarged detailsof the ribbed bar and,

hangers embedded in the concrete ribs.

The present system of ireproof-floor construction consists of haunehesof concret-e 1, resting on the lower flanges of adjacent I- 4o beams 2,incorporated into the building stru eture, a seriesof concrete ribs 3,extending from I-beam to I-beam, and a main door sheet or layer4 ofconcrete on said ribs and haunches and covering all the space betweenthe I- beams, all incorporated as one solid mass. The lower portion ofthe strengthening-ribs Sis thus submitted to tensile stress, and asconcrete has slight tensile strength a transversely ribbed or corrugatedbar or rod 5 of 5o steel-or other suitable metal of great tensilestrength is embedded in such lower portion. Although the bond betweenconcrete and metal is originally strong, such bond becomes strength.

Fig. 2 is a4 cross-section thereof.-

broken or weakened in the course of time by the ordinary use and Wear ofthe floor. For this reason transverse indentations or corrugations areformed in the bar, sothat, re`' gardless of the bond, the bar is soincorporated into the rib as to utilize its full tensile The bestarrangement of the in- 6o dentations or corrugations is in planes atright angles to the axis of the bar; but considerable variation in theirdirection is permissible. Theoretically such-variation is a function ofthe coeiiicient of friction between the concrete and metal, and thelimit of variation in any case is capable of computation as such; butunder ordinary circumstances such variations should not exceed fifteendegrees from the perpendicular plane above 7o defined. When theindentations or corrugations are inclined to the axis of the bar, theirrid ges act as wedges tending to split the concrete and in the case ofconsiderable variation from the plane above de'ned are very 75 liable todestroy the concrete strengtheningribs.

The next main feature of my invention after the corrugated bars is aloop 6 of pliable wire suspended astraddle such bars and 8o incorporatedwith them in the concrete ribs, but with its ends projecting below theooncrete. These ends are intended to extend through interstices in thesheets of expanded metal or other open-work metallic lathing andv to betwisted together on the under side of the lathing to hold said lathingfirmly up against the vribs as a foundation for the ceiling-plaster.A'ny other suitable form of hanger may be suspended from the 9o rod inlieu of the wire loop; but Iconsider such loop the most economical.

In operation my invention is carried out as follows: A centering orfalse work of the kind used for concrete ilooring is mounted on theI-beams in any suitable way. Then a thin layer of concrete is laid ineach ribcentering and a ribbed or corrugated bar of a lengthapproximately equal to the distance between the webs of the I-beams islaid thereroo on withoutbeing fastened. 'Wire loops are placed astraddlethe bar ats uitable intervals, with their ends projecting through thecentering, and then the concrete is filled in as in the ordinaryconcrete-flooring systems. Then the ribs are spaced farther apart thanusual and when the floor is required to be specially strong, expandedmetal, wire-cloth, or other similar material may be embedded in thelower portion of the main flooring layer to assist in carrying the loadbetween the ribs.

After the concrete has hardened, the centering or false work is removedand the ceilinglathing is fastened in place merely by passing it overthe projecting ends of the wire loops and twisting such ends together.The ceiling is thus held firmly up against the ribs.

There the ceiling is not required to be plastered, the wire hangers maybe omitted. So, also, a mere wire embedded in the concrete will serve tosuspend the ceiling hangers from, but will not materially strengthen theribs.

The sectional shape of the bar is practically immaterial in use and willtherefore depend largely upon the process of its manufacture andeconomical considerations. The ends of the bar, as Well as its middleportion, should be large enough to aord a firm bond with thc cement, andfor this and other considerations of economy the bar should be ofsubstantially uniform thickness throughout its length. The sectionalform of the indentations or corrugations also has a very wide range ofVariation and is determined very largely by the economy of manufacture.The proper sectional shape of the indentations is such that when the baris embedded in a cube of concrete of the thickness of thestrengthening-ribs and tested to destruction the bar will be pulled outwithout splitting the lconcrete. For practical and economical reasons Iprefer to use a bar of rectangular section, having in all four of itssides fiutes or scallops of semicircular section and arranged in planesperpendicular to the axis of the bar, as shown in Fig. 6.

The particular advantages of my fiooring, in addition to the saving inlabor and material, are that it increases the rigidity of the structureand increases the durability thereof. As the ceiling-hangers areincorporated in the concrete, they are firmly secured without injury tothe ribs and are in proper position to hold the ceiling firmly againstthe ribs. The ceiling is thus especially rigid and free from vibrationand is very inexpensive.

What I claim isl. In a concrete-and-metal construction, a slab ofconcrete having bars of metal embedded in the lower portion thereof,each of said bars being of substantially uniform thickness throughoutits length and having corrugations arranged in planes substantiallyperpendicular to the axis of the bar, substantially as described.

2. In a concrete-and-metal construction, a main slab of concrete havingribs of concrete on its under side, and a metal bar embedded in thelower portion of each rib, said bar being of substantially uniformthickness throughout its length and having corrugations arranged inplanes substantially perpendicular to the axis of the bar, substan--tially as described. l

23. In a concrcte-and-metal construction, a main slab of concrete havingexpanded metal or other open-Work metal in its lower portion, concreteribs on its under side and bars of lnetal embedded in the lower portionof said ribs, said bars being of substantially uniform thicknessthroughout their length and having corrugations arranged in planessubstantially perpendicular to the axis thereof, substantially asdescribed.

4. A concrete flooring comprising transversely corrugated bars embeddedin the lower portion of strengthening-ribs formed on the under side ofthe main slab, said bars being of substantially uniform thicknessthroughout their length substantially as described.

5. A iireproof flooring comprising I-beams, a layer of concreteextending from I-beam to I-beam, concrete ribs on the under side ol'said layer of concrete and arranged transversely to said I-beams, andtransversely-corrugated metal bars being of substantially uniformthickness throughout their length and embedded in the lower portion ofsaid ribs, substantially as described.

6. A fireproof iioor consisting of I-beams, concrete haunches resting onthe ianges thereof, concrete ribs extending from I-beam to I-beam on thelower side of the main floorslab and having transversely-corru gatedbars of substantially uniform thickness throughout their length embeddedin the lower porn tion thereof, and a main floor-slab of concreteresting on said ribs and haunches and having sheets of expanded metal orits equivalent embedded in the lower portion of said slab, substantiallyas described.

7 A iireproof flooring and ceiling construction comprising a mainiooring layer of concrete having strengthening-ribs on its under side,transversely-corrugated bars of substantially uniform thicknessthroughout their length embedded in said ribs, and ceilinghangerssuspended from said bars, substantially as described.

8. A lireproof ioor and ceiling construction comprising a flooring-slabof concrete extending from I-beam to I-beam, horizontalstrengthening-ribs on the underside thereof, unfastened rods embedded insaid ribs, ceiling-hangers suspended from said rods and metallic lathingheld up against said ribs by said hangers, substantially as described.

9. A :tireproof ioor and ceiling construction comprising a mainflooring-slab of concrete having horizontal ribs on its underside andunfastened rods embedded in said concrete, and pliable wire loopsstraddling said rods in the ribs and projecting below said ribs,substantially as and for the purpose set fort-h.

A. L. JOHNSON.

Witnesses:

JAMES A. CARR, j D. E. GARRIsoN.

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